The present invention is directed to a temperature sensor for a refrigeration system, and more particularly, to a fast response temperature probe for direct immersion in the refrigerant flow line of a refrigeration system.
The addition of microprocessors and electronic expansion valves to refrigeration systems has demonstrated the need for a fast response temperature probe located in the refrigerant flow lines. Such a probe must be protected from damage from the force of refrigerant flow and from errors resulting from gas or contaminant accumulations.
Previous probes for direct immersion in refrigerant flow lines such as the probe shown in U.S. Pat. No. 4,571,951 to Szymaszek have been encased in a hard protective shell to prevent damage to the probe from the force of the refrigerant flow when the probe is located in the refrigerant flow line. Such probes are not fast response probes due to the delay incurred while the temperature of the refrigerant penetrates the protective shell.
Other probes such as shown in U.S. Pat. No. 4,167,858 to Kojima et al. and U.S. Pat. No. 3,059,443 to Garner show fast response probes used for measuring gas and contaminants to determine refrigerant dryness, but these probes are located in pockets above the refrigerant flow line. These probes are not located in the refrigerant flow lines because the force of the refrigerant flow damages the sensing elements of these types of probes.
Similarly U.S. Pat. Nos. 4,090,371 to Keane and 4,653,288 to Sayao et al. show fast response temperature probes which are located in a compressor and a liquid tank respectively. These probes are not located in liquid refrigerant flow lines and are not protected from the turbulent flow of refrigerant in a liquid refrigerant flow line.